using System;

class PrimesToN
{
	static void Main()
	{
		//Write an expression that checks if given positive integer number n (n ? 100) is prime. E.g. 37 is prime.
		Console.WriteLine("Input number:");
		int number = Int32.Parse(Console.ReadLine());
		Console.WriteLine();
		if(number>=101)
		{
			return;
		}
		if (number % 2 == 0 || number % 3 == 0 || number % 5 == 0 || number % 7 == 0 )
		{
			if (number == 2 || number == 3 || number == 5 || number == 7)
			{
				Console.WriteLine(number + " is prime. \n");
				return;
			}
			Console.WriteLine(number + " is not prime.\n");
		}
		else
		{
			Console.WriteLine(number+" is prime. \n");
		}
	}
}